Electromechanical combination lock construction

ABSTRACT

AN ELECTROMECHANICAL COMBINATION LOCK CONSTRUCTION FORMED OF A PLURALITY OF DIAL ASSEMBLIES HAVING AN EXTERIOR, MANUALLY ROTATABLE DIAL AND A SHAFT FIXED THERETO CARRYING A FIRST WHEEL OF INSULATING MATERIAL WHICH HAS A RADIAL ELECTRICAL CONTACT FORMATION AT A PARTICULAR ANGULAR POSITION THEREON, AND ANOTEHR WHEEL MEMBER OF INSULATING MATERIAL WHICH IS MOVABLE BETWEEN FORWARD AND REARWARD POSITIONS AXIALLY OF THE SHAFT AND CARRIES A SPRING CONTACT MEMBER TO ENGAGE THE CONFORNTING FACE OF THE FIRST MEMTIONED WHEEL AND CLOSE AN ELECTRICAL CIRCUIT WITH THE CONTACT FORMATION ON THE FIRST MENTIONED WHEEL AT A PARTICULAR ANGULAR POSITION OF THE DIAL. AN EXPOSED LEVER, AND A CAM OPERATED THEREBY, CONTROL CERTAIN LIMIT SWITCHES AND ACTIVATE A DEVICE TO MECHANICALLY COUPLE THE REAR WHEELS WITH THE FRONT WHEELS FOR COORDINATE ROTATION WHEN THE LOCK IS IN UNLOCKED CONDITION AND TO SHIFT THE REAR WHEELS TO A DECOUPLED RELATION TO THE FRONT WHEELS WHEN THE LOCK IS MOVED TO LOCKED CONDITION. THE LEVER AND CAM ALSO CONTROL RETRACTING AND PROJECTING MOVEMENT OF A BOLT WHEN THE LATTER IS RELEASED BY ESTABLISHING AN ELECTRICAL CIRCUIT UPON DIALING OF THE PROPER COMBINATION.

c. SUBIETA v 3,625,033

ELECTROMECHANICAL COMBINATION LOCK CONSTRUCTION Dec. 7, 1971 4Sheets-Sheet 1 Filed Sept. 18,

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ELECTROMECHANICAL COMBINATION LOCK CONSTRUCTION Dec. 7, 1971 4Sheets-Sheet 2 Filed Sept. 18, 1970 INVENTOR CAmos suauewx ATTOIJZNEYSELECTROMECHANICAL COMBINATION LOCK CONSTRUCTION C. SUBIETA Dec. 7, 19714 Sheets-Shoot 5 Filed Sept.

INVIL'NTOR CARL-6S SUB'BTA WQZEK R M 2., ATTORNEYS ELECTROMECHANICALCOMBINATION LOCK CONSTRUCTION Filed Sept. 18, 1970 C. SUBIETA Dec. 7,1971 4 Sheets-$11001; 4

INVENTOR Cmnos S UBlETA ATTORNEYS United States Patent O 3,625,033ELECTROMECHANICAL COMBINATION LOCK CONSTRUCTION Carlos Subieta,Kensington, Md., assignor to Representation Unlimited, Washington, D.C.Filed Sept. 18, 1970, Ser. No. 73,359 Int. Cl. E05b 49/02; H01h 27/10US. Cl. 70-278 11 Claims ABSTRACT OF THE DISCLOSURE An electromechanicalcombination lock construction, formed of a plurality of dial assemblieshaving an exterior, manually rotatable dial and a shaft fixed theretocarrying a first wheel of insulating material which has a radialelectrical contact formation at a particular angular position thereon,and another wheel member of insulating material which is movable betweenforward and rearward positions axially of the shaft and carries a springcontact member to engage the confronting face of the first mentionedwheel and close an electrical circuit with the contact formation on thefirst mentioned wheel at a particular angular position of the dial. Anexposed lever, and a cam operated thereby, control certain limitswitches and activate a device to mechanically couple the rear wheelswith the front wheels for coordinate rotation when the lock is inunlocked condition and to shift the rear wheels to a decoupled relationto the front wheels when the lock is moved to locked condition. Thelever and cam also control retracting and projecting movement of a boltwhen the latter is relased by establishing an electrical circuit upondialing of the proper combination.

BACKGROUND AND OBJECTS OF THE INVENTION The present invention relates ingeneral to combination locking devices, and more particularly to anelectro mechanical combination lock construction wherein the combinationof the lock is whatever combination the dials were standing on at thetime the lock was last shifted to locked condition.

Heretofore, many combination lock structures have been made available,such as dial operated mechanical combination locks, dial operated orpush button operated electrical combination locks, or various types ofelectromechanical combination locks. Many of these have had provisionfor changing the combination of the lock whenever the security closureon .whichthe lock is mounted is in opened condition, usually byinsertion of a combination change key in the lock housing after aparticular change combination of numbers has been dialed, after whichthe dial or dials can be rotated to the new combination and the changekey removed to set the new combination. It is desirable in many uses ofcombination locks for high security purposes, to be able to frequentlychange the lock combination, such as on a daily basis or even moreoften. The conventional lock constructions and combination changemechanisms heretofore available involved combination change procedureswhich are sufficiently complex to render them inconvenient for suchfrequent changing of the lock combination.

An object of the present invention is the provision of a novelelectromechanical combination lock construction having a particularlysimple means of changing the combination such that the combination maybe readily changed any time the lock is in open or unlocked condition byrotating the dials to the new combination desired, and the newcombination is automaticallly set when the lock is returned to lockedcondition.

"ice

Another object of the present invention is the provision of a novelcombination lock construction as described in the preceding paragraph,wherein a plurality of independent rotatable dials, for example fourdials, are provided to form the total combination, so that a pluralityof dials must be independently and separately attacked to gainunauthorized entry.

Another object of the present invention is the provision of acombination lock construction as described in either of the twopreceding paragraphs, which resist unauthorized detection of thecombination through the use of listening devices, and which hasrelatively few components, facilitating reduced cost for massproduction.

Other objects, advantages and capabilities of the present invention willbecome apparent from the following detailed description, taken inconjunction with the accompanying drawings illustrating a preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a front elevation view of anelectromechanical combination lock construction embodying the presentinvention;

FIG. 2 is a rear elevation view, with the cover removed;

FIG. 3 is a vertical transverse section view taken along the line 3-3 ofFIG. 2, showing the contact carrying wheels associated with one of thedials with the lock unit in unlocked condition;

FIG. 4 is an exploded perspective view of an associated pair of thecontact carrying wheels;

FIG. 5 is a vertical transverse section view similar to FIG. 3, butshowing the contact carrying wheels in the position assumed when thelock unit is in locked condition;

FIG. 6 is a perspective view of the opening cam showing the open andclose limit switches and the wheel shifting bar assembly activatedthereby; and

FIG. 7 is a schematic diagram of the electrical circuit of the lock.

.2 DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring to thedrawings, wherein like reference characters designate correspondingparts throughout the several figures, the electromechanical lock of thepresent invention is indicated generally by the reference character 10and includes a housing 11 of any desired construction, which preferablywould have at least the front wall 12 thereof formed of hard platematerial which is resistant to drilling. The housing 11 may, forexample, have a removable rear cover plate 11a assembled to theremainder of the housing by any conventional means.

The basic operating elements of the lock assembly comprise a pluralityof manually operable dial units, generally indicated by the referencecharacter 13, four of which are provided in the illustrated embodimentand are designated by reference characters 13A to 13D. These dial units13 include a disc-like dial 14 having graduations and numbers adjacentthe circular periphery thereof and a knob 15 fixed thereto which may beof any desired form and is designed to facilitate manual rotation of thedial. It will be understood that any number of dial graduations may beemployed on each dial, such as ten graduations, fifty graduations, ofpreferably graduations. In the case of 100 dial graduations, if fourdials are employed, 100 million possible combinations Will be availablefor the lock. The dial assembly formed by the dial 14 and knob 15 ofeach dial unit is fixed to its respective shaft 16, which in theillustrated example in accomplished by a set screw 15a. The shaft 16 ofeach respective dial unit extends through the front wall of the lockhousing, and through any safe or file cabinet door or the like which maybe interposed between the lock housing and the dials, and has a pair ofwheel members 17 and 18 on each shaft 16 within the housing.

The forwardmost or front wheel members 17, which are of smaller diameterthan the rear wheel members 18, are fastened or fixed to theirrespective shafts 16 in any desired manner, either by being keyed to theshaft, or secured by set screws, or press fitted on the shaft, or by anyother known fastening means. These front wheels 17 are formed of acylindrical wheel body portion 17a of electrically non-conductive ordielectric material which has a center opening for its shaft 16 and aradial cut extending from its periphery close to but spaced slightlyfrom the center opening of the wheel. The radial cut is occupied by athin conductive sheet or strip 19 forming an electrical contact stripshaped to provide a completely smooth even surface at the cylindricalperiphery of the wheel and at the rear face of the wheel. The front faceof the wheel member 17 is covered by a circular metallic sheet 20 whichis fixed on the face of the nonconductive wheel portion by any suitableadhesive or bonding agent, and which is conductively joined to theradial thin conductive sheet 19. Forwardly, of the wheel member 17between the wheel member and the front wall 12 is a fiber panel 21having an opening through which the shaft 16 passes, forming a supportfor a pair of contacts 21a which are electrically connected together andto a wire conductor 22a and are in rubbing contact with the circularmetallic sheet on the front face of the front wheel 17. In theembodiment ilustrated, one fiber panel 21 is of sufficient length tospan forwardly across two of the wheel members 17 associated with thefirst two dial units 13A and 13B, and another fiber panel 21 spans thefront wheel members 17 associated with the dial units 130 and 13D andthese panels are resiliently urged rearwardly toward their associatedwheel members 17 by coil springs 23 surrounding the associated shafts 16and compressed between the fiber panel 21 and the front Wall 12 of thehousing 11.

The rear wheel 18 is freely movable axially of its associated shaft 16and also comprises a cylindrical nonconductive wheel body portion 18a,and has a substantially U-shaped contact support 24 formed of a springsheet member fastened at the ends of its legs 25 to the wheel bodyportion 18a by screws 25a and having a contact such as a button orcontact projection 26 supported on the bight or cross portion of theU-shaped spring contact support 24. The spring contact support 24 may bemade of phosphorous bronze or similar spring sheet material and the legscurved outwardly somewhat as illustrated in FIGS. 3 and to urge thecontact member 26 into rubbing engagement with the rear face of thewheel body portion 17a of front wheels 17 so as to engage the radialconductor strip or sheet 19 when the wheel member 17 is at a particularangular position relative to the wheel member 18. The U-shaped springcontact support 24 is electrically connected by a wire extending throughthe wheel body portion 18a, for example from one of the mounting screws25a, to an annular metallic sheet-27 fixed on the rear face of the wheelbody portion 18a in a manner similar to the means for fixing themetallic sheet 20 on the wheel member 17. A rear fiber panel 28, similarto the front fiber panel 21, is provided for example, one panel of whichspans across the wheel members 18 associated with the dial units 13A and13B, and another panel 28 which spans the wheel members 18 associatedwith the dial units 13C and 13D. These fiber panels 28 carry a pair offorwardly projecting contacts 28a arranged diametrically of theassociated shaft 16 to bear against and establish electric contact withthe annular metallic sheet 27 of the associated wheel member 18, the twocontacts 28a being electrically connected together and to a wireconductor 29a. The fiber panels 28 are apertured to receive the shafts16 of each of the dial units therethrough, and

coil springs 30 surround each of the shafts and are compressed betweenthe fiber panels 28 and a rear frame member 33 apertured to support therear ends of the shafts 16 to continuously urge the fiber panels 28forwardly.

Each of the front wheel members 17 carry a coupling pin or drive pin 31at an eccentric position thereon which projects rearwardly toward thecompanion rear wheel member 18 and is normally seated in a socket 32 inthe front face of the rear wheel member 18 when the rear wheel members18 are in the forwardly disposed unlocking position illustrated in FIG.3. Thus Whenever the associated dial and the forward wheel member 17 andassociated shaft 16 fixed relative to each other are rotated while therear wheel member 18 is in the forward position illustrated in FIG. 3,the companion wheel members 17 and 18 of each dial unit will beintercoupled together by the coupling pin 31 and socket 32 and will berotated in a coordinate manner. However, when the lock is shifted to alocked position, as illustrated in FIG. 5, the wheel members 18 areshifted rearwardly to decouple the pins 31 from the sockets 32 andrender the wheels 17 and their associated shafts and dials rotatableindependently of the associated rear wheel member 18. This isaccomplished by means of a bar assembly 34 comprising, in theillustrated example, a horizontal pivot bar 34a supported in pivotbrackets 34!) fixed to the lock housing and having bar members 340depending therefrom, if desired fastened together at their lower ends byanother horizontal cross bar 34c, wherein the bar members 340 haveportions which lie forwardly of the front faces of the rear wheelmembers 18 outwardly of the peripheries of the wheel members 17. Theseportions of the bar members 340 adjacent the front faces of the wheelmembers 18 may have frictional pad formations 34d, such as rubber pads,to engage diametrically opposite front face portions of the wheelmembers 18 when the bar assembly 34 is displaced rearwardly from itsnormal rearmost position. The lower or free end portion of the barassembly 34, which is formed by the lower cross bar 34:: in theillustrated embodiment, has a cam follower finger or tongue 34projecting therefrom rearwardly lapping the peripheral portion of arotatable control cam 35 journaled in the front wall of the lock housingbelow the bank of dial assemblies.

The control cam 35 in the illustrated embodiment is formed of acylindrical body 35a which is resiliently biased to a first orcounterclockwise limit position illustrated in FIG. 2 by a spring 36extending between an anchor pin 360: on the cam body 35a and astationaryanchor 36b, and having a drive pin 37 extending rearwardly through aslot 38a in a bolt 38 guided for reciprocative movement betweenprojected and retracted positions by guide brackets 39. A shaft 40 isfixed in relatively non-rotatable relation to the cylindrical body 35aof the control cam and projects to an exposed forward position where acontrol lever 41 is fixed to the forward end of the shaft. A cam strip35b is fixed to the periphery of the cylindrical body 35a of the cam 35along a portion of its circumferential extent and is positioned andshaped to engage the cam follower finger 34 of the bar assembly 34 andpivot the latter rearwardly during clockwise movement of the cam 35 tothe locking position illustrated in FIG. 2, during which the padformations 34d are brought into contact with the front faces of the rearwheel members 18 and shift them rearwardly along their associated shafts16 while retaining them against rotation to decouple the sockets 32 fromthe coupling pins 31. During the opposite or counterclockwise rotationof the control cam 35 from the locking position of FIG. 2 to theunlocking position, the cam follower finger 34f rides off of the camstrip 35b permitting the bar assembly 34 to pivot forwardly to theposition illustrated in FIG. 3, swinging the bar members 340 forwardlyand allowing the rear wheel members 18 to be urged forwardly by thesprings 30 to again couple the sockets 32 and coupling pins 31. Thecontrol cam 35 also has a pair of abutments or projections 42 and 43thereon to respectively activate first and second limit switches 44 and45 as will be later described.

The bolt 38 has first and second pairs of locking slots 38b and 38crespectively positioned to lie immediately to opposite sides of theguide brackets 39a when the bolt is in locking and unlocking positions,to receive the ends of legs 46a of a U-shaped staple member 46a fixed onthe end of a pivoted lever 46. The lever 46 is fixed on the pivot pin 47journaled in a supporting bracket 48 and has an angular extension 46bcoupled to the plunger 49a of a solenoid unit 49.

The electrical circuit of the lock is illustrated schematically in FIG.7, wherein the rotary switch is effectively formed by the companionpairs of wheel members 17 and 18 of the dial units 13A to 13D areindicated by reference characters S-A to SD respectively. These rotaryswitches S-A to S-D are connected in series circuit relation, forexample by connecting the wire 29a associated with the contacts 28a ofthe first dial unit 13A to the wire conductor 2211 connected to thecontacts 21a associated with the second dial assembly 13B, and similarlyinterconnecting the remaining dial units 13C and 13D to form the seriesrotary switch array. The wire conductor 22a associated with the firstdial unit 13A is connected by a conductor 51 through the first andsecond limit switches 44 and 45 and diode 52, for example an IN3492diode, to one terminal of a DC power source indicated schematically asbattery 53. This may take the form of a plurality of series connecteddry cell batteries of appropriate voltage rating, or mercury cells, orany other commercially available DC power source. The conductor 51connected to the left hand end of the array of rotary switches SA toS-D, as viewed in FIG. 7, is also connected by conductor 54 through asilicon controlled rectifier (SCR), to one end of the coil 4% of thesolenoid 49 whose other end is connected to ground, a capacitor C1 beingconnected across the solenoid coil 4%. The gate of the siliconcontrolled rectifier is connected through a resistor R1 to the conductor29a connected to the contacts 28a associated with the last dial assembly13D.

When the proper combination has been dialed on the dials of all fourdial units 13A to 13D, the contact 26 on the contact support springmember 24 carried by the wheel members 18 of each dial assembly will bein contact with the radial metallic strip or sheet 19 in each of thewheel members 17, completing the electrical circuit therebetween andeffectively closing all four of the rotary switches SA to SD. Thecontrol cam 35 must then be rotated a few degrees from the closedposition by operation of the control lever 41, rotating the camcounterclockwise as viewed in FIG. 2, to permit the limit switch 44 toclose, whereupon, since the other limit switch 45 is already closed,battery voltage is applied through the closed rotary switches to thegate of the silicon controlled rectifier and is impressed upon closureof the limit switch 44 across the silicon controlled rectifier, turningthe SCR on the allowing current to pass to the coil 49b of the openingsolenoid 49. The solenoid is thus energized, retracting its plunger 49a,which swings the lever 46 rearwardly to withdraw the ends of the legs ofstaple member 46a from looking slots 38b in the bolt 38, whereupon themovement of the drive pin 37 on the control cam 35 in the slot 38a willretract the bolt 38 to unlocking position. Also, during thecounterclockwise rotation of the control cam 35 to the unlocking limitposition, the cam strip 3512 was moved in such a way that progressivelyshallower portions engaged the cam follower finger 34 of the barassembly 34, allowing the bar assembly 34 to pivot forwardly to therelease position and consequently permitting the coil springs 30 toshift the fiber panels 28 and rear wheel members 18 forwardly to thepositions shown in FIG. 3 to seat the coupling pins 31 in the sockets 32so that the wheel members 17 and 18 are then intercoupled for coordinaterotation. Thus, when the lock is in this unlocked condition, the dials14 can be rotated to new combination positions. Then, upon manipulatingthe control lever 41 to rotate the control cam 35 back to the lockingposition, in a clockwise direction as viewed in FIG. 2, the action ofthe cam strip 35b on the cam follower finger 34 will shift the barassmebly 34 rearwardly bringing the pad formations 34d into engagementwith the front faces of the rear wheel members 18 and shifting themrearwardly along their shafts 16 a sufficient distance to decouple thepins 31 from the sockets 32 and leave the forward wheel members 17 freefor independent rotary movement relative to the rear wheel members 18.The rear wheel members 18 are restrained against angular movement fromthe positions to which they were adjusted when the dials were rotatedwhile the lock was open, because of the frictional engagement of the padformations 34d against the faces of the wheel members 18.

It will be appreciated that the abutment 43 engaging the limit switch 45at the end of the opening stroke of the control cam 35 opened the limitswitch 45, deenergizing the solenoid coil 49b and releasing the lever 46for spring return to latching relation with the bolt 38 wherein the endsof the staple 46a are inserted in the locking slots 380. Also uponreturn movement of the control cam 35 in a clockwise direction toreclose the lock, the solenoid coil 4% is again energized to withdrawthe latching staple 45a from the bolt locking slots as soon as theabutment 43 leaves the limit switch 45, and engagement of the abutment42 with the limit switch 44 at the closed limit position of the controlcam 35 again breaks the supply circuit to the solenoid coil 49b so thatthe spring 46a returns the lever 46 to the latching position.

To provide a means for opening the lock in the event of power failure ofthe batteries 53, another diode 52a is connected in parallel with thediode 52 to a lead 52a which may terminate in a jack or contact on andinsulated from the front wall, to the connected to an exterior DC sourcewhen needed to prevent a lockout.

What is claimed is:

1. An electromechanical combination lock comprising a plurality ofrotatable dial assemblies forming rotary switch units to be angularlyadjusted to various positions for dialing the combination of the lock;each dial assembly having a manually rotatable dial and a shaft rotatedthereby, a first wheel member fixed on the shaft having a firstelectrically conductive. contact at an eccentric location thereon, asecond wheel member rotatably and axially movable relative to the shafthaving a second electrically conductive contact carried at an eccentriclocation thereon to engage the first contact of the companion firstwheel member at one angular position thereof during relative rotation ofthe wheel members; operating means including a manually operable memberfor shifting the lock between locked and unlocked conditions, meansblocking said shifting except when said contacts of each of therespective dial assemblies are in engagement, coupling means forreleasibly coupling each second wheel member to its companion wheelmember for coordinate rotation when the lock is in unlocked condition,and means for decoupling said wheel members fro-m each other responsiveto shifting of the lock to locked condition whereby the second wheelmembers remain at the angular positions which they last occupied whenthe lock is shifted from unlocked to locked condition.

2. An electromechanical combination lock as defined in claim 1,including a reciprocative bolt, said operating means including arotatable cam having an eccentric pin for moving said bolt betweenlocking and unlocking positions, and pivoted positioning means moved bysaid cam for moving said second wheel members axially away from thefirst wheel members during shifting of the lock to locked condition todecouple them and for releasing the second wheel members to coupledpositions relative to the first wheel members during shifting of the'lock to unlocked condition.

3. An electromechanical combination lock as defined in claim 1, whereinsaid first wheel members are each formed of a cylindrical wheel body ofelectrically nonconductive material having a narrow radial cuttherethrough spaced from said shaft and occupied by electricallyconductive material terminating flush with the rear face of the wheelbody and forming said first contact, an annular layer of electricallyconductive material on the front face of the wheel body electricallyconnected with the material in said cut, and said lock includingstationary contactors in continuous wiping engagement with the layer ofconductive material during rotation of the first wheel members tocontinuously establish circuit connections from stationary conductors tothe conductive material in said cuts.

4. An electromechanical combination lock as defined in claim 2, whereinsaid first wheel members are each formed of a cylindrical wheel body ofelectrically nonconductive material having a narrow radial outtherethrough spaced from said shaft and occupied by electricallyconductive material terminating flush with the rear face of the wheelbody and forming said first contact, an annular layer of electricallyconductive material on the front face of the wheel body electricallyconnected with the material in said cut, and said lock includingstationary contactors in continuous Wiping engagement with the layer ofconductive material during rotation of the first wheel members tocontinuously establish circuit connections from stationary conductors tothe conductive material in said cuts.

5. An electromechanical combination lock as defined in claim 1, whereinsaid second wheel members are each formed of a cylindrical wheel body ofelectrically nonconductive material, a U-shaped electrically conductivespring member fastened at the free end portions of its legs to the wheelbody and having a contact button carried on the bight portion of thespring member, said second wheel members being movable axially on theirrespective shafts from first positions closely adjacent and coupled tothe companion first wheel members to second positions spaced anddecoupled from the companion first wheel members, said spring membersbeing shaped to continuously urge the buttons thereof into rubbingcontact with the confronting rear face of the companion first wheelmembers at both said first and second positions of the second wheelmembers.

6. An electromechanical combination lock as defined in claim 2, whereinsaid second wheel members are each formed of a cylindrical wheel body ofelectrically nonconductive material, a U-shaped electrically conductivespring member fastened at the free end portions of its legs to the wheelbody and having a contact button carried on the bight portion of thespring member, said second wheel members being movable axially on theirrespective shafts from first positions closely adjacent and coupled tothe companion first wheel members to second positions spaced anddecoupled from the companion first wheel members, said spring membersbeing shaped to continuously urge the buttons thereof into rubbingcontact with the confronting rear face of the companion first wheelmembers at both said first and second positions of the second wheelmembers.

7. An electromechanical combination lock as defined in claim 3, whereinsaid second wheel members are each formed of a cylindrical wheel body ofelectrically nonconductive material, a U-shaped electrically conductivespring member fastened at the free end portions of its legs to the wheelbody and having a contact button carried on the bight portion of thespring member, said second wheel members being movable axially on theirrespective shafts from first positions closely adjacent and coupled tothe companion first wheel members to second positions spaced anddecoupled from the companion first wheel members, said spring membersbeing shaped to continuously urge the buttons thereof into rubbingcontact with the confronting rear face of the companion first wheelmembers at both said first and second positions of the second wheelmembers, an annular layer of electrically conductive material on therear face of the wheel body of each of said second wheel memberselectrically connected to said spring member, and rear stationarycontactors in continuous wiping engagement with the layer of conductivematerial on said rear face to establish circuit connections fromstationary conductors to said contact buttons.

8. An electromechanical combination lock as defined in claim 4, whereinsaid second wheel members are each formed of a cylindrical wheel body ofelectrically nonconductive material, a U-shaped electrically conductivespring member fastened at the free end portions of its legs to the wheelbody and having a contact button carried on the bight portion of thespring member, said second wheel members being movably axially on theirrespective shafts from first positions closely adjacent and coupled tothe companion first wheel members to second positions spaced anddecoupled from the companion first wheel members, said spring membersbeing shaped to con tinuously urge the buttons thereof into rubbingcontact with the confronting rear face of the companion first wheelmembers at both said first and second positions of the second wheelmembers, an annular layer of electrically conductive material on therear face of the wheel body of each of said second Wheel memberselectrically connected to said spring member, and rear stationarycontactors in continuous wiping engagement with the layer of conductivematerial on said rear face to establish circuit connections fromstationary conductors to said contact buttons.

9. An electromechanical combination look as defined in claim 2, whereinsaid second wheel members are of larger diameter than said first wheelmembers, said pivoted positioning means comprising a frame having aplurality of arms which forwardly lap peripheral portions of the frontfaces of said second wheel members projecting radially beyond the firstwheel members, said arms being movable between forward positions spacedout of engagement with the second wheel members and rearward positionsengaging and shifting the second wheel members to positions decouplingthem from their companion first wheel members.

10. An electromechanical combination lock as defined in claim 8, whereinsaid second wheel members are of larger diameter than said first wheelmembers, said pivoted positioning means comprising a frame having aplurality of arms which forwardly lap peripheral portions of the frontfaces of said second wheel members projecting radially beyond the firstwheel members, said arms being movable between forward positions spacedout of engagement with the second wheel members and rearward positionsengaging and shifting the second wheel members to positions decouplingthem from their companion first wheel members.

11. A combination lock comprising a plurality of rotatable dialassemblies forming rotary dial units to be angularly adjusted to variouspositions for dialing the combination of the lock; each dial assemblyhaving a manually rotatable dial and a shaft rotated thereby, a firstwheel member fixed on the shaft having a first lock releasing formationat an eccentric location thereon, a second wheel member rotatably andaxially movable relative to the shaft having a second lock releasingformation carried at an eccentric location thereon to assume a selectedposition relative to the first releasing formation of the companionfirst wheel member for establishing a release condition of the wheelmembers of the dial assembly at one angular position thereof duringrelative rotation of the Wheel members; operating means including amanually operable member for shifting the lock between locked andunlocked conditions when said first and second lock releasing formationsof each of the respective dial assemblies assume said release condition,means for preventing actuation of said operating means to shift the lockto unlocked condition when the wheel members of any of said dialassemblies donot occupy said release condition, coupling means activeonly when the lock is in unlocked condition for releasibly coupling eachsaid second wheel member to its companion wheel member for coordinatedrotation, and means for decoupling said wheel members from each otherresponsive to shltting of the lock to locked condition where-by thesecond wheel members remain at the angular positions References CitedUNITED STATES PATENTS 5/ 1926- Tueckmantel 70 -315 X 7/1968 Massengale20043 ALBERT G. CRAIG, 111., Primary Examiner U.S. Cl. X.R. 70-315;200-43

